The present invention relates to an improved mixing accessory. More particularly, the present invention relates to a mixing accessory having two Moebius shaped mixing blades arranged to promote high mixing efficiency of the ingredients to be mixed and thereby producing a more uniform mixture.
Attempts have been made to provide mixing accessories which generate a more uniform mixture of the ingredients to be mixed. These attempts are described as follows.
U.S. Pat. No. 4,615,623, discloses a mixing accessory having blades mounted by their end faces at two spots on a central shaft. The blades are an arc-like design, their ends being twisted at an angle of 90 degrees. The developed view of the two blades as a whole is an S-like figure with a straight portion near the area of the shaft at which the blades are attached and rounded areas at the ends of the figure. The mid-line of the S-like figure is straight at the shaft axis. At this area the blades are mounted on the shaft along the normal to its axis. But the angle of the mid-line of one blade is 180 degrees, i.e. the limiting points of the figure are connected by a straight line passing through the shaft axis. The modified blade has separated parts mounted on a tubular shaft.
USSR inventor's certificate #903130, BOIF 7/24, 1982 discloses a mixing accessory that includes a vertical shaft with a primary mixing blade in the shape of a one-sided surface like a Moebius strip and at least one auxiliary blade shaped to form a helix. The auxiliary blade is mounted on the shaft at some angle with respect to the main one. The two strips are fixed on the shaft at the diametrical generatrices.
The prior art devices have many limitations. In particular, the mixing accessory of the U.S. Pat. No. 4,615,623 patent cannot reach high mixing efficiency. At high rotation speeds of 5000 to 8000 RPM (typical of the state-of-the-art mixers) the effect of mixing along the shaft axis vanishes because the axial velocity is very low in comparison with the tangential one. Ingredients will only be rotated, not mixed, since they move in parallel to each other.
The mixing accessory of the 903130 inventors certificate is not capable of providing high efficiency of mixing and requires much energy and time for treatment.